1. Field of the Invention
The present invention relates to an assignment method for assigning tone information of a solo tone to a tone generator channel, an electronic musical instrument having an assign function of assigning tone information of a solo tone to a tone generator channel, and a storage medium which computer-readably stores steps of assign processing for assigning tone information of a solo tone to a tone generator channel.
2. Description of the Prior Art
As a conventional method of assigning tone information of a solo tone to a tone generator channel, two different assignment methods, i.e., permanent assignment and dynamic assignment are available, and one of these methods is used in electronic musical instruments and the like.
In the permanent assignment method, a tone generator channel (to be also simply referred to as a channel hereinafter) for a solo tone is prepared in advance, and the tone information of the solo tone is always assigned to that channel prepared in advance.
By contrast, in the dynamic assignment method, no tone generator channel for a solo tone is particularly assigned, and all the tone generator channels are shared by the solo tone and other tones.
However, in the permanent assignment method, when the next key-ON event is detected during generation of a solo tone, the solo tone that is being generated is cut off, and a new solo tone is generated. At this time, an identical tone generator channel (that for a solo tone) is used. That is, since cutoff of the currently generated solo tone and generation of a new solo tone must be switched in an identical tone generator channel within a short period of time, noise is often produced.
In order to avoid such noise from being produced, another permanent assignment method is known. In this method, not one but two or three tone generator channels including an auxiliary tone generator channel are prepared in advance as those for a solo tone, and one of these tone generator channels is adaptively selected and used.
However, when such a method is used, a plurality of tone generator channels is often occupied by one solo tone to be generated in the instrument.
On the other hand, in the above-mentioned conventional dynamic assignment method, when all the tone generator channels are occupied, and a tone corresponding to the latest ON event is preferentially assigned, a solo tone and other tones may conflict to result in cutting off each others' tones.
The aforementioned problem is especially conspicuous when a solo tone is continuously generated. Conventionally, a solo tone cannot be satisfactorily obtained due to noise produced when a solo tone next to the currently generated solo tone is to be generated.